I'm not familiar with this. But I would guess it's like changing the language setting in a device from say English to French. All of the screen text is then French, and unless you can read French, the device is unusable.
When the printer is connected to a device that "speaks" olivetti, the printer will likely work fine. But other devices connected to the printer (which are speaking IBM) can no longer see/communicate with the printer...hence the error.
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